SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '209fe636e100df6d31542f4db1659b4e0e58507c0290f38695054209d4363b06' 
  AND token = 'OvSLSNaFnNN0BvXXBCPvWvsRBqEs6KhYcZzcqpg99Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}